1. Field of the Invention
The field of the invention relates to signage generally, and more particularly to certain new and useful advances in the application of energy-efficient light emitting diodes (LEDs) to signs and displays.
2. Description of Related Art
Various configurations exist for illuminating a sign or a display. For example, front-lit signs are illuminated using one or more light sources that are exterior to the sign. Back-lit signs are illuminated using one or more light sources, most commonly fluorescent bulbs, which emit light by ionizing mercury vapor. The ionized mercury vapor emits ultraviolet light. The ultraviolet light impinges a phosphor coated on the inside of the fluorescent bulb, causing the phosphor to fluoresce, giving off light. Non-electrical signs are illuminated using a radioluminescent material such as tritium. Some signs form graphics and/or words out of a tube that is filled with a gas, such as neon, argon or krypton. The gas emits light when electrical energy passes from an electrode at one end of the tube through the gas to an electrode at the other end of the tube.
More recently, edge-lit signs have been developed. These illuminate flat, thin sign faces by inputting light from multiple edges of the sign face. One or more LEDs can be used as light sources, but due to heat and physical design constraints, but those used tend to be low-power LEDs. Moreover, such LEDs typically have a fixed geometry that is sized for a specific sign face size or application.